Implantable medical devices used for patient treatment can be a source of microbial infection in such patients. For example, insertion or implantation of a medical device into a patient can introduce microbes that can cause infection. To reduce or minimize the impact of the introduction of microbes to a patient, many medical devices, such as catheters, have been coated with antimicrobial agents.
However, many antimicrobial agents that are useful in coating medical devices tend to be insoluble in formulations used to coat the device and tend to form agglomerated particles on the surface of the medical device. These agglomerated particles increase the surface roughness of the medical device, thus increasing the chance for thrombus formation on the surface of the medical device, and are more readily detached from the surface thereby reducing the long term efficacy of the antimicrobial coating. Further, agglomerated particles in the antimicrobial formulation that is used to coat the medical device may lead to active material precipitating out of the formulation and therefore not being coated onto the medical device, or otherwise interfering with the coating process. Accordingly, a need exists for improved antimicrobial coatings on implantable medical devices.